![]() Albinism is associated with fiber over-decussation, resulting in crossing of up to 90% of fibers to the contralateral side and thus strabismus and loss of stereopsis. Abnormal decussation of the visual pathways: Normally about half of optic nerve fibers from each eye decussates at the optic chiasm to the contralateral side, contributing to stereopsis.Foveal hypoplasia is the single most important contributor to poor vision in albino patients. Also, the foveal avascular zone is small or nonexistent with vessels crossing the area 2 disc diameter temporal to the optic disc margin. Optical coherence tomography (OCT) can demonstrate an absence of the foveal pit and the loss of normal thinning of the retina. Foveal hypoplasia (absence of a foveal pit): In albinism, the retina does not develop normally before birth and in infancy because of inappropriate retinal pigment epithelium (RPE) pigmentation that is required for macular development.Eye muscle surgery may be considered to reduce nystagmus. Affected infants may have large amplitude with low frequency pattern of eye movement starting at 2-3 months of age, later changing to a pendular form without distinct fast or slow phases. Pendular nystagmus: Nystagmus refers to rhythmic, involuntary, conjugate eye movement.The iris may be translucent and the margin of the crystalline lens may be visible on transillumunation during slit lamp examination. When present in an otherwise normal individual, this finding may indicate carrier status of a hypomelanotic gene mutation. This finding, while common with albinism, is not specific as iris transillumination occurs in diseases unrelated to albinism such as pseudoexfoliation, pigment dispersion syndrome, megalocornea, iris atrophy, and Axenfeld-Rieger spectrum. On slit lamp exam, the examiner may detect speckled or diffuse transillumination defect. Iris transillumination: The iris in albinism has little to no pigment to screen out stray light coming into the eye.OCT of a patient with albinism showing foveal hypoplasia Ī number of features in combination paint the picture of albinism. ![]() In certain localities in Africa, however, the prevalence is estimated to be as high as 1 in 1,000 possibly as a result of consanguinity, and is a notable regional public health issue. These heterogeneous groups of the relatively rare genetic condition affecting the tyrosine/melanin biochemical cascade are estimated to occur worldwide at a range of 1 in 5,000 to 1 in 40,000 (about 1 in 37,000 in America). The disorder can be divided into two groups: oculocutaneous albinism (OCA)-the most common condition among hypopigmentation disorders -with varying degrees of involvement of the eyes, hair, and skin the second group is the less common group called ocular albinism (OA) with disease involvement limited to the eyes. All races of the human species can be affected, although the phenotype is more recognizable in dark-skinned individuals. 2.3.6.1 Differentiation of Syndromes with Silvery HairĪlbinism refers to reduced pigmentation compared to others of the same racial background, with characteristic eye involvement.2.2.9.1 Mutations detected in genes associated with albinism. ![]()
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